High-tension suspension-insulator.



S BARFOED men TENSION SUSPENSION INSULATOR.

APPLICATION FILED JULY 26.1915.

Patented Feb. 19, 1918.

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. member 3, the surface of which may be cor- UNITED sTArEs PATENT OFFICE.

SVEND BARFOED, OF OAKLAND, CALIFORNI A.

Specification of Letters Patent. Patented Feb. 19, 1918.

, Application filed July 26, 1915. Serial No. 41,914.

To all whom it may concern:

Be known that I, SvENn BAnFonn, a subject of the Kingof Denmark, residing at Oakland, in the county of Alameda and State of California, have invented new and useful Improvements in High-Tension Suspension-Insulators, of which the following is a specification. v

This invention relates to a high tension suspension insulator. 1

One of the objects of the present invention is to provide a simple form of suspension insulator provided with means for creating an electrostatic field-of uniform intensity about the insulator proper, and to design or shape the insulator in such a manner that it will present surfaces parallel to the lines of electrostatic force created in the field. Another'object is to provide an insulator in which fracturefrom shearing strain is entirely eliminated. Another object is to provide means for safeguarding insulators against damage-from arcing between units. Further objects will hereinafter appear.

The invention consists of the parts and the construction and combination of parts. as hereinafter -more fully described and claimed, having reference to the accompanying drawings, in which V. Figure 1 is a view of a tower and cross insulators.

Fig. 2 is a cross section of a pair of connected-insulators.

Fig. 3 is a side elevation of same.

Fig. 4; is a side elevation of a modified form of insulator.

Referring in detail to the drawings, A indicates in general a single insulator, which consists of a metal cylinder 2, interiorly of which is secured a disk-shaped. insulating rugated, as at 4, to produce a creepage surface. Extending centrally through the insulator 3-and the cylinder 2 is across beam 5, on the outer ends of which aresecured suspension links 6 forming a means for connecting a string fashion, such as shown in F1 1.

Suspension insulators in genera where two or more are employed to support a hi h tension line, such as indicated at 7 are su 'ected to more or less weight, and the insulators proper are, therefore, sub ected to more or less shearing train, by reason of the weight carried by the cross beam This is rm, showing the application of-a string of statlc lines of force cross or intersect the inlurality of insulating units in The cement by which the insulator is secured 4 to the beam in some instances is similarly prevented from fracture, andthe life and efliciency of the device as a whole prolonged or increased;

The insulating disk 3 may be secured on the beam in any suitable manner, either by cement,,clips, clamps or by being pressed thereon, as the disk proper maybe made of various materials, such as micarta, fiber, vulcanized rubber, glass, porcelain, or other material. Similarly, th links 6, forming a connection between the several insulators in a string, may be constructed of various materials; the insulating efliciency beingv greatly increased where the links are constructed of micarta. 1

The provision of the cylindrical-shaped, metal cylinder produces a uniform electrostatatic field about the insulator proper and also causes the lines of electrostatic force created in the field to run parallel with the insulators now in use, the electrostatic field in and around the insulating body proper is poorly distributed, due to unfavorable proportion and shape of the metallic electrodes and 'of the dielectric or insulating body proper. The result is concentration of electrical stress giving rise to corona formation,

arc over and puncture during voltage impulses with steep wave fronts, such as occur during lightning strokes, switching and arcing rounds. Failures also occur from mechanical defects, caused principallyby the use of cementin assembling the'insulator proper,.with its iron parts, to produce a rigid bond between the materials of a different coefficient of expansion. This r sults in high internal stresses in the porcelain during temperature changes, causing fracture and other damage. Crystalline growths also take place in the cement under certain circumstances, adding further stress and fracture. Furthermore, in sustaining the external load, by means of shearing stresses, surfaces between the iron parts and the porcelain parts must be of such length that the load may be properly supported. This shearing strain tends to bend the insulator and consequently either fractures same or destroy the bond between the diiferent arts. p In the present invention all these defects have been entirely overcome as the bearing surface in the porcelain insulator is so small, when compared with the length of the beam, that any bending of the beam will have no effect on the porcelain insulator. The bond between the beam and insulator may, therefore, be made by cement or any other-suitable means without p-roducingthe failures heretofore described. Furthermore, the lll'll-r form field established by the metal cylinders surrounding the beam and insulator produces a uniform electrostatic field in which the lines of electrostatic force run parallel with the surface of the insulator, thus preventing concentration of the lines of force or intersection of the insulating body proper. I

In the present invention means have also been provided for preventing the insulator from becoming damaged during arc-overs between units caused by lightning strokes, or the like. This means consists of metallic disks 8, of circular shape, and in cross sectiOn similar to the segment of a sphere. These metallic disks are electrically and mechanically connected to an encircling band 9 on the metal cylinder 2; this band being provided both for the purpose of supporting the metallic shield 8 and the transmission wire 7. These disks may be renewed if destroyed by the power are which often produces sufiicient heat to practically consume the shield before the current is cut oil at the power house. The insulator proper, with surrounding cylinder 2 and center beam 5, together with connecting links 6 are thus saved from destruction during arcing over between units which, as previously described,

may take place during lightning strokes or grounding of one of the conductors, and as the metal shields may be easily renewed, it has proven' a great economical feature as far as cost or maintenance of power lines is concerned.

In Fig. 4 a modification of the type shown in Figs. 1, 2 and 3 is shown. In this instance two or more cylindrical-shaped, corrugated insulators are employed, as indicated at 11, to support the beam concentric with relation to the cylinder 2, the insulating efliciency being practically the same in either instance.

The materials and finish of the several parts of the mechanism are such as the experience and judgment of the manufacturer may dictate.

centrically positioned within same, and an insulating member mounted within the cylinder between its ends and interposed between the beam and cylinder to support the beam.

2. In a high tension suspension insulator, a metal cylinder opened throughout its length, a disk-shaped insulator secured within the cylinder between its ends, and a beam extending through the insulator and cylinder and concentrically positioned with relation to same.

3. In a high tension suspension insulator, a metal cylinder, a disk-shaped insulator secured within the cylinder, a beam extending through the insulator and; cylinder and concentrically positioned with relation to same, a clamping band exteriorly of the cylinder, and an arcing plate carried by the band.

4. The combination with a plurality of insulators, of an arcing plate arranged on each insulator in opposing relation to the plate on the adjacent insulator.

5. In a high tension suspension insulator,

a metal cylinder, a disk-sha ed insulator secured within the cylinder, a cam extending through the insulator and cylinder and concentrically positioned with relation "to same, a link on each end of the beam, means from which said links are suspended, a clamping ring surrounding the metal cylin- "der, and means for suspending a transmission line from the clamping ring.

6. In a high tension suspension insulator, a cylinder opened at both ends, a diskshaped insulator secured within the cylin:

. der and having its opposite faces corrugated,

and a wire-suspension .beam extending beam extending through each cylinder and its insulator, means joining the respective ends of the. beams together, and an arcing plate earned by each cylinder in opposing relation to each other.

9. In a high tension suspension insulator,

a pair of cylinders, an insulator in each, a my hand in the presence of two subscribing beam extending through each cylinder and Witnesses. its insulator, means joining the respective ends of the beams together, a band encir- SVEND BARFOED" 5 cling each cylinder, and an arcing plate se- Witnesses: cured to each cylinder by the band. JOHN H. HERRING,

In testimony whereof I have hereunto set W. W. HEALEY. 

